Method for disassembling a battery housing of a high-voltage battery system

ABSTRACT

A method for disassembling a battery housing of a high-voltage battery system, in particular of a vehicle, in which housing parts of the battery housing are in material connection with each other along joining flanges, wherein for disassembling the battery housing a disassembly tool is inserted into a joining gap between the joining flanges to loosen the material connection.

This nonprovisional application claims priority under 35 U.S.C. § 119(a)to German Patent Application No. 10 2021 204 685.1, which was filed inGermany on May 10, 2021, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a method for disassembling a batteryhousing of a high-voltage battery system, a disassembly tool and use ofthe disassembly tool for disassembling a battery housing.

Description of the Background Art

The battery housing of a high-voltage battery system can be constructedfrom two housing halves, namely a housing base (i.e., battery tray) anda housing cover. After installation of all battery components (i.e.,modules, wiring harnesses, power electronics), the two halves of thehousing must be connected to each other in such a way that tightness andthus safety is ensured over the service life of the battery system. Forthis purpose, the housing halves can be glued together.

In a generic method for disassembling a battery housing, a disassemblytool is inserted into a joining gap between the joining flanges ofbattery housing parts glued together to loosen the adhesive bond.

The technical problem is to open the housing halves glued together inthe shortest possible process time and with reliable repeatability in anautomated process. In the prior art, the adhesive connection is usuallycut open manually with an oscillating saw. Care must be taken to ensurethat the saw teeth do not break off or that too high a temperature isintroduced by friction, so that the housing parts re-glue after thecutting process.

Such a cutting process can be carried out with great effort on the partof workers as well as by means of crushing tools. It has been shown thata cutting process with an oscillating saw cannot be transferred to afully automated series process for disassembling the battery housing. Inaddition, in the prior art, the personnel costs for disassembling thebattery housing are comparatively high. A slight, incorrect loading onthe saws can lead to breakage of the saw teeth (of the saw blade). Inaddition, excessive heat exposure during the cutting process can lead tore-gluing of the battery housing parts.

From DE 10 2018 211 637 A1 a device for opening a prismatic battery cellis known, and from DE 10 2016 107 372 A1 a housing for receivinghigh-voltage components is known, which are both herein incorporated byreference.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodfor disassembling a battery housing of a high-voltage battery system,which is simple and reliable in comparison to the prior art in terms ofmanufacturing technology.

An exemplary embodiment of the invention is based on a method fordisassembling a battery housing of a high-voltage battery system inwhich housing parts of the battery housing are at least in materialconnection with each other (sometimes additionally screwed together)along joining flanges. To disassemble the battery housing, a disassemblytool is inserted into a joining gap between the joining flanges toloosen the material connection. According to the characterizing portionof claim 1, the disassembly tool is realized as a rotary cutter. Duringthe disassembly process, this is inserted into the joining gap in aninfeed movement in the joining flange transverse direction over apenetration depth and rolled off in a forward movement along the flangeconnection in the longitudinal direction of the joining flange.

Specifically, the material connection can be an adhesive bond in whichthe two joining flanges are glued together with an intermediate adhesivelayer.

A core idea of the invention is that opening the battery housing isrealized as a multi-stage process of cutting, damaging, and pressing thetwo housing parts. In the method, the disassembly tool can be insertedinto the adhesive seam, which damages the latter. Subsequently, anadditional mechanical separation force (hereinafter referred to as thelever force) builds up through the further insertion of the disassemblytool, which force is introduced into the two housing parts via thedisassembly tool. The initiated lever force pushes the two housing partsapart.

The disassembly tool, that is, the rotary cutter, may preferably havetwo design areas, namely a first design area which is very flat andsharp as a blade to damage the bonding when penetrating. In the seconddesign area, the tool thickness increases to press the housing halves bymeans of the deeper penetration of the tool. The combined use of bothdesign areas of the rotary cutter causes the battery housing to open.

By using the rotary cutter, the disassembly process can be easilyautomated using robot support with regard to a large-scale industrialapplication, which gains in economic importance in particular with thereturn of high quantities of used batteries.

According to the invention, damage to the adhesive connection using anoscillating saw and levering apart the housing carried out as separateprocess steps are thus dispensed with. Rather, the core of the inventionincludes the combination of a cutting force that is damaging to theadhesive seam and a lever force for opening the housing halves.

By way of example, the tool can be attached to a robot arm andautomatically inserted into the adhesive seam between the two housingparts. The robot arm then moves along the battery contour following theadhesive seam. By adjusting the penetration depth into the adhesiveseam, the intensity of the pressing of the two housing parts can bevaried and controlled.

In general, the rotary cutter can have a motor-driven, electric rotarydrive, so that the cutting process is realized as a milling process. Inthis case, the robot moves along the battery contour and separates thehousing parts by milling.

With such a milling process, however, only a reduced feed and thus onlya low overall process speed can be realized due to the heat input. Inaddition, the milling process is associated with chip formation. Themilling chips can penetrate into the inside of the housing and possiblycause short circuits there. In addition, when such milling is used, itis no longer possible to trace exactly which foreign bodies havepenetrated into the housing interior due to the milling process andwhich foreign bodies have penetrated the inside of the housing over thebattery life, which limits the applicability of the milling process, ora subsequent analysis of the foreign bodies found. In addition, afterthe milling process, a residue of the other housing part usually remainson one housing part. Therefore, no homogeneous separation of thematerials is possible, which is disadvantageous with regard to sortedwaste or material separation.

Thus, it is preferred if the rotary cutter is freely rotatable about arotation axis. In this case, the rotary drive of the rotary cutter takesplace passively, that is, as a result of the forward movement withoutany additional, external electrical energy.

In the following, aspects of the invention are again emphasized indetail: This means the material connection between the joining flangescan extend in the joining flange transverse direction over a flangewidth. Preferably, the penetration depth of the rotary cutter may beless than this flange width. This ensures the following process control:after the cutting process has been carried out, a residual materialconnection remains between the joining flanges over a residual flangewidth. Following the cutting process, a lever operation can be carriedout in which the two joining flanges are pushed apart with a lever forceso that the residual material connection tears open.

The two joining flanges can be in material connection with each other ata joining plane. With regard to flawless disassembly processing, therotation axis of the rotary cutter can be aligned at right angles to thejoining plane.

In a technical implementation, the cutting blade geometry can berotationally symmetrical to the axis of rotation. The cutting bladegeometry can be realized in such a way that both the cutting process andthe levering process are carried out by the rotary cutter. For thispurpose, the cutting blade may have a cutting blade bottom, inparticular aligned at right angles to the axis of rotation. This canform a flat cone angle with a radial outer, circumferential cuttingflank. The radial outer cutting flank can merge into a radially inner,circumferential lever flank at a transition edge. This can form a steepcone angle with the cutting blade bottom. In this case, the followingprocess control results: in the course of the infeed movement of therotary cutter, an outer part of one of the joining flanges can come intosliding contact with the radial inner lever flank of the cutting bladeuntil the penetration depth is reached. This builds up a lever force bymeans of which the two joining flanges are pushed apart.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are not limitiveof the present invention, and wherein:

FIG. 1 is a rotary cutter in a perspective representation, and

FIGS. 2 and 3 are, respectively, views illustrating a disassemblyprocess.

DETAILED DESCRIPTION

FIG. 1 indicates a battery housing 1 of a high-voltage battery system,which is composed of two halves of the housing, namely a battery tray 3and a battery cover 5. Battery components (such as battery modules,wiring harnesses and power electronics) that are not shown are arrangedinside the housing. The two housing halves 3, 5 each have joiningflanges 7 protruding from the outside of the housing, which are bondedtogether and in which the two joining flanges 7 are glued together at ajoining plane F with an intermediate adhesive layer 9. The flangeconnection thus formed runs in a flange longitudinal direction x overthe entire battery housing circumference. In FIG. 1 or 3, the adhesiveconnection extends in a joining flange transverse direction y over aflange width b.

The disassembly of the battery housing 1 can be carried outrobot-assisted. For this purpose, a disassembly tool 11 is provided inFIG. 1. The disassembly tool 11 is realized as a rotary cutter with acircular disc-shaped cutting blade 13. This is rotatably mounted about arotation axis R on a bearing console 15. The bearing console 15 can bemounted via a base plate 17 on an unseen distal end of a robot arm.

In the following, the cutting blade geometry, which is rotationallysymmetrical to the rotation axis R, is described on the basis of thefigures: Accordingly, the cutting blade 13 has a cutting blade bottom 19aligned perpendicular to the rotation axis R. This forms a flat coneangle α (FIG. 3) with a radially outer, circumferential cutting flank21. The radially outer cutting flank 21 merges at a transition edge 23into a radially inner, circumferential lever flank 25, which forms asteep cone angle β (FIG. 3) with the cutting blade bottom 19.

By means of the cutting blade geometry described above, the disassemblyprocess illustrated below on the basis of FIGS. 2 and 3 can be carriedout: First, the cutting blade 13 is inserted in an infeed movement f_(y)in the joining flange transverse direction y over a penetration depthΔy₁ (FIG. 3) into a joining gap 27 between the two joining flanges 7. InFIG. 3, the penetration depth Δy₁ of the rotary cutter 11 is smallerthan the flange width b. This means that after the infeed movementf_(y), a residual adhesive bond remains between the joining flanges 7over a residual flange width Δy₂.

A forward movement f_(x) of the rotary cutter 11 along the flangeconnection in the joining flange longitudinal direction x issuperimposed in time on the infeed movement f_(y) or temporally followsthe infeed movement f_(y). During the forward movement f_(x), thecircular disc-shaped cutting blade 13 rolls off passively whileseparating the adhesive connection in the longitudinal direction of thejoining flange x. In the infeed movement f_(y) and the forward movementf_(x), the cutting blade bottom 19 is supported in sliding contact onthe facing, lower joining flange 7.

In the course of the infeed movement f_(y), until reaching thepenetration depth Δy₁, the upper joining flange 7 with its outer edge 31(FIG. 2) comes into sliding contact with the lever flank 25 of thecutting blade 13, whereby a lever force F_(A) builds up, by means ofwhich the two joining flanges 7 are pushed apart.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are to beincluded within the scope of the following claims.

What is claimed is:
 1. A method for disassembling a battery housing of ahigh-voltage battery system in a vehicle, in which housing parts of thebattery housing are in material connection with each other along joiningflanges, the method comprising: inserting, for the disassembly of thebattery housing, a disassembly tool into a joining gap between thejoining flanges in order to loosen the material connection, thedisassembly tool being a rotary cutter; inserting the rotary cutter intothe joining gap in an infeed movement in the joining flange in atransverse direction over a penetration depth while separating thematerial connection; and rolling off the rotary cutter in a forwardmovement along the flange connection in the joining flange longitudinaldirection.
 2. The method according to claim 1, wherein the materialconnection between the two joining flanges extends in the joining flangetransverse direction over a flange width, and wherein the penetrationdepth of the rotary cutter is less than the flange width so that aftersuccessful cutting or after completion of the infeed movement there isstill a residual material connection between the joining flanges over aresidual flange width, and wherein after the cutting process, a leveringprocess takes place, in which a lever force builds up via which the twojoining flanges are pressed apart so that the remaining residualmaterial connection tears open.
 3. The method according to claim 1,wherein the two joining flanges are in material connection with eachother at a joining plane and/or wherein the rotary cutter rolls offduring the forward movement about an axis of rotation, which is alignedat right angles to the joining plane.
 4. The method according to claim1, wherein the rotary cutter is not assigned a rotary drive operated byexternal energy, and wherein the rotary cutter only passively rolls offduring the forward movement without its own rotary drive.
 5. The methodaccording to claim 1, wherein the material connection is an adhesiveconnection in which the two joining flanges are glued together with anintermediate adhesive layer.
 6. The method according to claim 1, whereinthe rotary cutter has a circular disc-shaped cutting blade, which isfreely rotatably mounted about a rotation axis.
 7. The method accordingto claim 6, wherein the cutting blade geometry is rotationallysymmetrical with respect to the axis of rotation and/or wherein thecutting blade geometry is designed such that both the cutting processand the levering process are carried out via the rotary cutter.
 8. Themethod according to claim 7, wherein the cutting blade has a cuttingblade bottom, which is aligned substantially perpendicular to the axisof rotation and which is supported in the cutting process and/or in thelevering process on one of the joining flanges, and/or wherein thecutting blade bottom forms a flat cone angle with an outer radial,circumferential cutting flank and/or wherein the radial outer cuttingflank merges into a radial inner, circumferential lever flank at acircumferential transition edge, which lever flank forms a steep coneangle with the cutting blade bottom such that in the course of theinfeed movement or the forward movement, an outer portion of one of thejoining flanges comes into sliding contact with the radial inner leverflank, whereby the two joining flanges are pushed apart by the leverforce.
 9. A disassembly tool for the method according to claim
 1. 10.The disassembly tool according to claim 9, wherein the disassembly toolis a rotary cutter.